Red Currant Bakery

0 Brew or buy your espresso! It will take time to brew this much espresso so start that before the next steps or head to your local coffee shop for espresso.
1 Strong coffee technically works in a pinch but I find the flavor really gets lost and doesn't balance out well.
Chocolate Cookie Crust
3 Add all of the chocolate sandwich cookies (filling and all) into a blender. If using a small blender do this in two batches. Blend until smooth.In a medium mixing bowl, melt down the salted butter in the microwave.
4 Pour the cookie crumbs into the bowl with the melted butter. Stir to combine. If the cookies still feel like they can't be pressed together at all add a little more butter.
5 Press the cookie crust into the tart shell. Press it first into the sides of the pan and then into the base. Use the bottom and sides of a metal measuring cup to smooth out and really press the crust into the pan. It should reach all the way to the top of the pan.
6 Place the pan on a baking sheet and put it in the freezer to set while you work on the next steps.
Chocolate Ganache
8 Roughly chop the chocolate and then add it into a medium heat safe bowl.
9 In a large glass measuring cup or a pot, add in the cream and heat in the microwave or stove until steaming not boiling.
10 Pour the hot cream over the chocolate and place a lid or cutting board over the bowl for one minute.
11 Remove the lid and use a whisk to slowly whisk the chocolate and heavy cream together until smooth. Add in the salted butter and whisk once more.
12 Pour the smooth chocolate ganache into the frozen tart shell. Use a pastry brush or the back of a spoon to bring the ganache up the sides of the tart. 
13 Then smooth out the surface of the remaining ganache at the bottom of the tart. Place it back into the freezer to set while you make the pastry cream.
Sour Cream Pastry Cream
15 In a medium sauce pot, add in the sugar and cornstarch (or whichever starch you're using) and whisk together.
16 Pour in the milk and whisk again.
17 Add in the egg yolks and salt and whisk once more.
18 Place the pot over medium low heat. Whisking regularly being sure to scrape the sides and bottom of the pot as you whisk.
19 Cook until thick and one or two bubbles happen. Don't let it come to a boil. It will look weird and lumpy at first but remove it from the heat, whisk vigorously and it'll smooth out.
20 Remove the pot from the heat and pass it through a fine mesh sieve into a larger mixing bowl. Whisk in the sour cream and vanilla until smooth.
21 Lay a piece of plastic over the surface of the cream and allow it to cool down to room temperature.
22 Once cooled (doesn't need to be fridge cold but should no longer be warm), whip the cold heavy cream in a medium bowl until medium stiff peaks form. Use a flat rubber spatula to fold the whipped cream into the sour cream pastry cream.
Assemble
24 Take the tart out of the freezer. Slice the bananas in half lengthwise place them cut side down over the chocolate ganache. Break the bananas into different lengths as needed to fit them into the pan.
25 Spoon 1/3 of the pastry cream over the bananas and use an offset spatula or the back of a spoon to smooth it out.
26 Pour the espresso into a small dish, one at a time dunk the lady fingers into the espresso. I usually do about 3 seconds on each side. Then cover the surface of the cream with one layer of soaked lady fingers. I usually use about 10 per layer.
27 Spoon another third of the pastry cream over the lady finger layer and repeat with another layer of lady fingers and then the rest of the cream.
28 For this layer of lady fingers, try not to let them get too close to the edge because they will be above the edge of the tart pan and you want to be able to cover the edges with the cream.
29 Smooth out the pastry cream on the top and sides as best you can and then cover the surface with a layer of plastic wrap. Store the tart in the fridge ideally overnight but at least 6-8 hours.
30 When ready to serve, remove the plastic wrap and carefully press the tart base up and out of the shell.
31 Loosen along the edges where the base and edges of the tart shell connect, if you press just from the center you have a higher chance of the crust breaking.
32 I recommend leaving this on the tart base for serving because it isn't the most robust crust - which is ideal for eating but less ideal for moving around. Just before serving, dust the top of the tart with cocoa powder.
33 Slice with a big sharp knife straight down through the tart. Clean the knife between each cut to get beautiful clean slices.